The U.S. Supreme Court on Monday declined to enter the fray over when a health insurance plan administrator is allowed to raise new grounds for denying a claim for medical benefits, an issue which has divided the federal courts of appeal.

The high court denied a request by Blue Shield of California to decide whether a health insurance plan covered by the Employee Retirement Income Security Act (ERISA) is entitled to provide an initial explanation for denying a beneficiary coverage and to then, later on, assert new reasons for refusing coverage. ?...

Some circuits, including the 5th and 7th Circuits, say that a health plan does not waive the right to assert a new argument that was not included in the initial letter. Others, including the 1st and 2nd Circuits, consider whether the company had enough information to raise the argument when the first letter was sent. Others, including the 9th and 10th Circuits, consider a defense waived if the plan failed to assert it up front. ?...

The patchwork of different rules complicates the picture for large employer plans with national reach, said John Pope, an employee benefits lawyer at Epstein Becker & Green not involved in the case. ?...

I get calls from people saying 'Will you look at my denial letter' They're reaching out to legal counsel at the first stage to make sure they've covered all their bases," Pope said.